An IP phone switch is a phone system switch which has ports for connections to data networks to enable telephone connectivity and voice transport, and may further include connections to a public switched telephone network (PSN). A data network herein includes at least one of a local area network (LAN), a wide area network (WAN), and the global Internet. IP phone switches feature Voice over the Internet (VoIP) or IP telephony. VoIP is anticipated to replace the PSTN as the dominant voice transport system in due course.
The development of IP telephony has resulted in IP-based network telephone systems for enterprises. Such systems have IP phones. Each IP phone is programmed with a unique Media Access Control (MAC) address that allows it to be recognized by the IP phone switch at any point in the network. Each IP phone and its associated communications server communicate over a local area network (LAN) using an IP address (layer 3) and MAC address (layer 2). The IP phone switches are programmed with a list of valid MAC addresses and their associated telephone numbers, extension numbers or directory numbers. Typically such MAC addresses are manually entered into an IP phone switch.
The disadvantages of manual entry of MAC addresses include attendant keyboarding errors, and difficulty in re-associating the directory numbers with other MAC addresses when people move within an enterprise.